Yet Another Paint Color

DH cringes every time we walk by our local home improvement store's paint department.  Why?  Well, I—yep, I—have painted the kitchen, sunroom, and hallways twice!  Too dark, too faint, too green, not blue enough.  I've learned a few things along the way, but with so many possibilities, I admit I get carried away.   If painting were as easy as getting a mani or dye job, I would probably be that lunatic who changes room colors every two weeks.  

OPI Russian Navy
Source: Behindthescenesmakeup.com

However, painting is not that easy, especially when I really suck at cutting edges and insist on taping.  

I thought a friend's recent choice in bedroom paint color, Benjamin Moore’s Ocean Floor which looks amazing with her white fabric headboard, was it; however, I then found a new hue of blue while surfing a friend's Facebook pictures— Behr's Silent Tide PMD-55.  

Could this be it??  What do you think?  Why is picking paint color so darn hard?